Conveying meaning through design in a safety critical medical system
Medication errors account for a significant number of medical errors. Giving medications to patients is an activity that carries a high risk of error. In an effort to improve patient safety in this area several approaches have been employed. Many of these have taken a systems approach in that they consider how organisational factors such as medicines management, staffing levels, ward layout, shift patterns and staff training have contributed to the errors. None of these studies describe errors in detailed form at task level. This Thesis addresses the gap in knowledge by presenting a systematic analysis of the component tasks of hospital drug administration where none exists and goes on to describe novel design artefacts that assist the identification of drugs. The thesis highlights how hierarchical task analysis, a human factors technique, can be applied to the hospital drug administration task. Task analysis techniques have been used in many high-risk domains in industry as a means of analysing human activity in complex systems but remains an underused technique in health care. Used with the Systematic Human Error Reduction and Prediction Approach (SHERPA), hierarchical task analysis provides an effective way of predicting where errors in the drug administration task are likely to occur. SHERPA uses a taxonomy of human error modes to highlight types of error and makes suggestions to reduce these errors. Medication errors take many forms however it was decided to focus on the immediate interaction between the nurse and the patient. The measures considered to potentially have a significant influence were adding conspicuous labelling to medication packages. These were enhanced by icons intended to represent categories of drugs. Constructing a three dimensional representation of the icon design was considered to provide nurses with an additional channel of information. Technological solutions were proposed and a patient identity bracelet that uses a programmable chip to link the patient to their prescribed medication was viewed as having a huge potential to simplify the checking aspect of administering medications in which the nurse compares a medication order which is often badly written with available drug stock. The device prevents nurses giving medications to the wrong patient. It also prevents them administering an overdose.